The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Cellular network based mobile devices are becoming standard vehicle equipment. A cellular network based mobile device of a vehicle may have to be at least partially running even when the engine of the vehicle is turned off. However, due to restrictions on consuming current from the battery of the vehicle (i.e., auxiliary power of the vehicle), the mobile device may have to turn itself off after a certain time period.
To do so, the auxiliary-powered mobile device may maintain an accurate and uninterruptable clock (i.e., run clock-based logic). One method to maintain the accurate clock is to power the clock with another battery. However, the additional battery may be costly and may itself run out of power to maintain the clock.
Another method to maintain the accurate clock is to synchronize the clock with the cellular network when either the engine or the battery of the vehicle is powering the clock. However, the cellular network may not be available to synchronize the clock. The mobile device may be in a region that does not allow for access to the cellular network. In addition, in both cases, the mobile device may suffer a power glitch that disrupts the clock. Therefore, a new method of determining whether the auxiliary-powered mobile device has to turn itself off is desired.